This is my favorite game of all time.

I highly recommend going in blind, so all I'll say is this: It's a game about exploration and discovery within a solar system. It's perfectly sized so that it feels huge while still keeping exploration manageable. Every new discovery hints at something even more interesting.
The only reason to ignore this game is if you hate reading, but you should really try to push through that.
Outer Wilds is an incredible experience.